Consumption of noncarbonated fruit and vegetable juices has greatly increased since 1950 due to technological breakthroughs in the juice processing and concentration industry. Better quality, better tasting and higher purity juice products which are more convenient to use have been developed.
The challenge of producing beverages which are acceptable to a broad range of consumers involves making a unique product having an acceptable flavor, distinctive aroma, acceptable appearance and satisfactory mouthfeel. The aroma and flavor ingredients and the level of sugars affect each of these characteristics.
Consumers are becoming more calorie conscious and also concerned about the total amount of sugars consumed daily. A good tasting beverage which is low in calories and low in sugars is desirable. There is also a need to retain the vitamins and other nutrients, including fibers (pectin) present in the fruit juice.
During the process of concentrating beverages, especially those involving evaporation, a significant portion of the aroma and flavor volatiles are removed with the water vapors. These volatiles consist of various alcohols, esters, aldehydes, ketones, acids, etc. This loss results in a significant deterioration in quality and overall flavor of the concentrated beverage.
Evaporation processes involve heating the beverage under conditions which promote hydrolysis and/or oxidation of components of the beverage. This causes chemical alterations of the aroma and flavor compounds as well as other materials. For instance, lipids can be oxidized and the amino acids and sugars can undergo browning reactions. Such degradation products can cause off flavors in the concentrated beverage. Thus, conventional evaporation processes frequently result in off-flavors and flavor loss in the juice product produced. Pectin and pulp in the beverage adsorb aroma and flavor components which also contributes to lower display of aroma and flavor levels.
It is generally recognized that while evaporation concentration processes are useful and fairly effective, there is still a significant loss of aroma and flavor compounds which occurs.
Numerous methods have been devised to compensate for the loss of aroma and flavor during evaporation concentration processes. For instance, U.S. Pat. No. 4,463,025, Strobel, issued July 31, 1984, discloses a process for preparing a fruit juice concentrate prepared from natural citrus fruit ingredients. This process involves freeze concentration. The citrus fruit juice concentrate has at least 35% solids including pulp, non-volatile compounds, pectin and volatile compounds. This citrus fruit juice concentrate has at least 65% of the aroma and flavor volatile compounds of the natural juice. (See also U.S. Pat. No. 4,374,865 to Strobel (1983), which claims a concentrated orange juice).
U.S. Pat. No. 3,248,233 Brent et al., issued Apr. 26, 1966, discloses a method of minimizing the overall loss of aroma and flavor compounds by collecting "essence" of the juice. Essence is the term applied to the first 15% to 20% of the water which is removed through evaporation and which contains a significant amount of volatile aroma and flavor compounds. The escaping essence is condensed, the aroma and flavor compounds recovered and rectified as water is removed, and then added back to concentrated juice. U.S. Pat. No. 3,140,187 Brent, et al, issued July 7, 1964, discloses a juice concentration method.
U.S. Pat. No. 3,118,776, Byer et al., issued Jan. 21, 1964, discloses a multi-step process for recovering the volatile flavor fraction from fruit juices at temperatures of less than 120.degree. F. (49.degree. C.). In a closed system, a thin continuous film of citrus juice is distributed over a heat exchange surface at a substantially reduced pressure to partially concentrate the juice by separating it into two components. The minor fraction containing the aroma and flavor volatiles is condensed and removed. After another separation, the remaining mixture is distilled at a temperature below 100.degree. F. (38.degree. C.) and a pressure of less than 1.5 inches mercury (57.5 mm Hg).
U.S. Pat. No. 2,641,550, Dykstra et al, issued June 9, 1953, discloses the removal of volatiles from orange juice via heating, evaporating under vacuum or by stripping with an inert gas, e.g., nitrogen. Three condensers are used to condense the vapors. The first-stage condenser is maintained at 32.degree. F. (0.degree. C.) to 85.degree. F. (29.degree. C.); 90% to 98% of the distillate is removed. This first fraction is discarded. The second stage condenser is maintained at 32.degree. F. (0.degree. C.) to -95.degree. F. (-139.degree. C.), while the third stage condenser is maintained below -130.degree. F. (-202.degree. C.). The distillates recovered from the second and third stage condensers are later added to the orange juice concentrate.
Each of these procedures is not totally satisfactory because only a fraction of the escaping aroma and flavor volatile compounds can be collected and recovered. Thus, there is necessarily a significant loss in the overall aroma and flavor of the final concentrated product.
Others have tried different procedures for adding back certain volatile compounds and essences to concentrated beverages to enhance the overall flavor and consumer acceptability of the juice. For example, Ahmed et al, J. Agri. Food Chemistry, 26,2, 368-372 (1978), describe the addition of certain volatile compounds and essences to juice concentrate after their recovery from the evaporator. The objective was to match the aroma and flavor found in fresh orange juice.
The process herein is able to remove the volatiles in less than a second versus an hour for vacuum distillation and minutes for other evaporation techniques using film or plate evaporators.
Others have tried fermentation as a means of making low calorie juices. Swiss patent No. 632,137 (1978) discloses an alcohol free low calorie fruit juice made by fermentation or enzymatic conversion of sugar in juice. The sugar free juice is combined with a natural juice at a ratio of 1 to 1. Alternatively, the sugar free juice can be sweetened using an artificial sweetener to provide a very low calorie juice. Apple juice can be used in this process. In this procedure, the aroma and flavor is removed with the alcohol, not before the fermentation.
The process herein separates the aroma and flavor volatiles from pasteurized fruit juice. The deflavored juice is fermented with yeast to remove sugar by converting it into alcohol, carbon dioxide, and water. After fermentation, the alcohol is removed from the apple juice, along with any additional flavors produced by fermentation. This then removes any off-flavors and aromas from the yeast reaction. The alcohol fraction can be combined with the previously separated aroma and flavor volatiles to make a "fruit" brandy. The juice without the sugars is concentrated and the aroma and flavor volatiles are added back. The low calorie juice can be artificially sweetened or mixed with other juices.
Therefore, it is an object of the present invention to provide a process for producing a lower calorie fruit beverage or beverage concentrate which contains at least 75%, and in some instances as much as 90% or more of the aroma and flavor volatiles present immediately after extraction of the juice.
It is a further object of this invention to produce a juice, and in particular, an apple juice, which is lower in sugar and calories by hydrolyzing the sugars using yeast and then removing the alcohol without degrading or totally removing the aroma and flavor volatiles.
It is still a further object of this invention to provide a means for pasteurizing a juice beverage before the separation of the aroma and flavor components and the sugar.
It is also an object of this invention to remove substantially all of the oxygen from a juice beverage in order to prevent flavor degradation due to caramelization of the sugar, browning reactions, oxidation of phenolic and lipid components, and other chemical oxidation reactions of the aroma and flavor volatiles.
These and other objects of this invention will become apparent by the description of the invention below.